The present invention relates to an embossing system and, more particularly, to a system for embossing characters on a medium such as a plastic credit card, identification card, or membership card and performing such embossing functions under automated control.
Automated embossing systems are widely known in the field. Prior systems are disclosed in U.S. Pat. No. 4,378,733 to Polad et al. and U.S. Pat. No. 4,088,216 to LaManna et al. and in U.S. patent application Ser. No. 204,499 to Warwick et al. filed June 9, 1988. Each of these systems are used for embossing operations having similar speeds and throughput rates.
The Polad and LaManna systems employ a complicated mechanism to achieve the embossing. Embossing wheels mount embossing punch blocks and die blocks which are struck by large bail arms requiring a complex linkage having a number of moving parts. The large bail arms require ample space for proper operations. The associated linkage is relatively expensive and must be properly adjusted for maintaining the consistent embossing height required in embossing operations. With a complicated linkage such as the prior art, skilled technicians are required for these adjustments, increasing maintenance costs. The large number of moving parts also increases the occurrences of malfunctions or misalignments, thereby reducing reliability and performance.
The LaManna patent implements individual return springs for each character block for returning the character block to a home position after the embossing stroke. The individual return springs for each character block require extensive assembly time and greatly increase manufacturing costs.
The Warwick et al. application discloses an embossing drive apparatus wherein solenoids drive the hammers without the use of bail arms. The application discloses return springs on each character block and a return plate (90) shown in FIG. 1 for returning character blocks to a home position. The return plate mounts on the solenoid and pulls the character block back when the plunger returns to its at rest deenergized position. A spring (62) forces the plunger back to the at rest position.
Another known return device is a flexible disk engaging the inside edge of the ring of character blocks. The flexible disk is unsatisfactory as it develops unwanted stresses, is prone to wear and does not set the character blocks in a straight position for embossing.
Other problems encountered with prior systems are inconsistent emboss height and card bowing. The character block ends of the bail arms do not always stop at the same position during each stroke, thereby embossing some characters at different heights. The card is not properly supported in prior systems during embossing, resulting in card bowing. As the punch and die engage the card, the card tends to bow toward the punch side around the character location without card support on the punch side of the card. Bowing is aesthetically unpleasing and leads to problems in encoding and reading magnetic stripes on cards.
It is evident that the prior art does not satisfy the need for a low cost embossing apparatus which obtains consistent emboss height and reduces card bowing. The prior art does not have a satisfactory low cost method for returning character blocks following embossing. The present invention solves these and other problems associated with embossing mechanisms.